When you connect your device with a computer for the first time, an alert asks whether you trust the PC. If you accidentally tap "Untrust" or forget to tap "Trust" in time, 3uTools will prompt "Failed to Trust" or "Trust Timeout".

Solution: To fix this, you can replug your device and then tap "Trust" on your device.

# Problem description 3

If you enable USB Accessories in iOS 11.4.1 or later, your device should have this pop-up since your iPhone was locked over one hour. And it probably one of the reasons caused you failed to connect your device with 3uTools.

Solution: Just unlock your iPhone and tap "Trust". The toggle next to USB Accessories is off by default.